<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>

</head>
<body>
    <ul>
        <li>list1</li>
        <li>list2</li>
    </ul>
</body>
<script src="jquery.3.4.1.js"></script>
<script>
    $('li:first').html('<a href="http://www.mi.com">爽歪歪</a>')   //a标签

    var a = document.createElement('a')
    a.innerText = '我是AD钙'
    $('li:last').html(a)     //a 是dom对象



    var a2 = document.createElement('a')
    var jqobj = $(a2)
    jqobj.text('乳娃娃')
    $('li:last').html(jqobj)   //jqobj是jquery对象
</script>
</html>